1. Field
The present patent specification relates to an apparatus and method for image processing, and more particularly to an apparatus and method for image processing which is capable of accelerating an image overlay process by detecting and omitting an image overlaid.
2. Discussion
Japanese Laid-Open Patent Application Publication No. 10-233859 explains a conventional technology in which superimposed image data are output on a recording sheet. In the above-mentioned technology, overlaid image data are detected by a printer driver for determining specific image data that are overlaid and data transfer to a printing medium may decrease by omitting a part of image data which are overlaid. Thereby, data processing in printing is also expected to decrease by means of replacing overlaid part of image data to produce identical color image data. In another example of conventional technology, Japanese Laid-Open Patent Application Publication No. 10-333852 describes a technology in which coordinates of the circumscribed rectangles of characters and figures, not limited to graphic image data, are obtained, abstraction of the obtained coordinates of the circumscribed rectangle is performed and an overlay of image data is detected with reference to the coordinates of the rectangle. In Japanese Laid-Open Patent Application Publication No. 11-119930, the time when rendering of image data is finished is anticipated and when it is determined that the rendering of image data may not be further developed at a predetermined interval thereafter, overlaid image data portion is detected between overlaid intermediate data whose rendering range of characters or graphics is divided in every trapezoid. The above-described conventional overlay detection technologies in which image data which are overlaid are detected on the side of a printer driver have a defect in that the above-described technologies are specific and limited to image data and in that as a result information processing for omitting overlaid portion of image data increases.